A host computer connects to a data network via a host interface to a network interface controller A sideband interface connects the network interface controller to a baseboard management controller having a management network port for connection to a management network. A path is established in the network interface controller between the host interface the basement management controller via the sideband interface of the network interface controller to conduct data selectively between the management network and either the host central processing unit and the or internally in the network interface controller.